Commit 6f8e35e2 authored by Eric Blake's avatar Eric Blake Committed by Kevin Wolf
Browse files

backup: Switch backup_run() to byte-based 



We are gradually converting to byte-based interfaces, as they are
easier to reason about than sector-based.  Change the internal
loop iteration of backups to track by bytes instead of sectors
(although we are still guaranteed that we iterate by steps that
are cluster-aligned).

Signed-off-by: default avatarEric Blake <eblake@redhat.com>
Reviewed-by: default avatarJohn Snow <jsnow@redhat.com>
Reviewed-by: default avatarJeff Cody <jcody@redhat.com>
Reviewed-by: default avatarKevin Wolf <kwolf@redhat.com>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 03f5d60b

block/backup.c

+15 −17
Original line number Diff line number Diff line
@@ -370,11 +370,10 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job) 
    int ret = 0;

    int clusters_per_iter;

    uint32_t granularity;

    int64_t sector;

    int64_t offset;

    int64_t cluster;

    int64_t end;

    int64_t last_cluster = -1;

    int64_t sectors_per_cluster = cluster_size_sectors(job);

    BdrvDirtyBitmapIter *dbi;



    granularity = bdrv_dirty_bitmap_granularity(job->sync_bitmap);
@@ -382,8 +381,8 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job) 
    dbi = bdrv_dirty_iter_new(job->sync_bitmap, 0);



    /* Find the next dirty sector(s) */

    while ((sector = bdrv_dirty_iter_next(dbi)) != -1) {

        cluster = sector / sectors_per_cluster;

    while ((offset = bdrv_dirty_iter_next(dbi) * BDRV_SECTOR_SIZE) >= 0) {

        cluster = offset / job->cluster_size;



        /* Fake progress updates for any clusters we skipped */

        if (cluster != last_cluster + 1) {
@@ -410,7 +409,8 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job) 
        /* If the bitmap granularity is smaller than the backup granularity,

         * we need to advance the iterator pointer to the next cluster. */

        if (granularity < job->cluster_size) {

            bdrv_set_dirty_iter(dbi, cluster * sectors_per_cluster);

            bdrv_set_dirty_iter(dbi,

                                cluster * job->cluster_size / BDRV_SECTOR_SIZE);

        }



        last_cluster = cluster - 1;
@@ -432,17 +432,15 @@ static void coroutine_fn backup_run(void *opaque) 
    BackupBlockJob *job = opaque;

    BackupCompleteData *data;

    BlockDriverState *bs = blk_bs(job->common.blk);

    int64_t start, end;

    int64_t offset;

    int64_t sectors_per_cluster = cluster_size_sectors(job);

    int ret = 0;



    QLIST_INIT(&job->inflight_reqs);

    qemu_co_rwlock_init(&job->flush_rwlock);



    start = 0;

    end = DIV_ROUND_UP(job->common.len, job->cluster_size);



    job->done_bitmap = bitmap_new(end);

    job->done_bitmap = bitmap_new(DIV_ROUND_UP(job->common.len,

                                               job->cluster_size));



    job->before_write.notify = backup_before_write_notify;

    bdrv_add_before_write_notifier(bs, &job->before_write);
@@ -457,7 +455,8 @@ static void coroutine_fn backup_run(void *opaque) 
        ret = backup_run_incremental(job);

    } else {

        /* Both FULL and TOP SYNC_MODE's require copying.. */

        for (; start < end; start++) {

        for (offset = 0; offset < job->common.len;

             offset += job->cluster_size) {

            bool error_is_read;

            int alloced = 0;
@@ -480,7 +479,7 @@ static void coroutine_fn backup_run(void *opaque) 
                     * needed but at some point that is always the case. */

                    alloced =

                        bdrv_is_allocated(bs,

                                start * sectors_per_cluster + i,

                                          (offset >> BDRV_SECTOR_BITS) + i,

                                          sectors_per_cluster - i, &n);

                    i += n;
@@ -499,9 +498,8 @@ static void coroutine_fn backup_run(void *opaque) 
            if (alloced < 0) {

                ret = alloced;

            } else {

                ret = backup_do_cow(job, start * job->cluster_size,

                                    job->cluster_size, &error_is_read,

                                    false);

                ret = backup_do_cow(job, offset, job->cluster_size,

                                    &error_is_read, false);

            }

            if (ret < 0) {

                /* Depending on error action, fail now or retry cluster */
@@ -510,7 +508,7 @@ static void coroutine_fn backup_run(void *opaque) 
                if (action == BLOCK_ERROR_ACTION_REPORT) {

                    break;

                } else {

                    start--;

                    offset -= job->cluster_size;

                    continue;

                }

            }